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Design of a high voltage delivery system for noble liquid time projection chambers

R. Saldanha, L. Pagani, E. Angelico, E. P. Bernard, B. Chana, S. Delaquis, R. DeVoe, M. Elbeltagi, S. Ferrara, D. Goeldi, R. Gornea, A. Odian, G. S. Ortega, C. T. Overman, L. Placzek, P. C. Rowson, K. Skarpaas, F. Spadoni, P. Acharya, A. Amy, A. Anker, I. J. Arnquist, A. Atencio, J. Bane, V. Belov, T. Bhatta, A. Bolotnikov, J. Breslin, P. A. Breur, E. Brown, T. Brunner, B. Burnell, E. Caden G. F. Cao, L. Q. Cao, D. Cesmecioglu, D. Chernyak, M. Chiu, R. Collister, M. Marquis, T. Daniels, L. Darroch, M. L. di Vacri, Y. Y. Ding, M. J. Dolinski, B. Eckert, A. Emara, N. Fatemighomi, W. Fairbank, B. Foust, D. Gallacher, N. Gallice, A. Gaur, W. Gillis, F. Girard, G. Gratta, C. A. Hardy, S. Hedges, E. Hein, J. D. Holt, A. Iverson, X. S. Jiang, A. Karelin, D. Keblbeck, A. Kuchenkov, K. S. Kumar, A. Larson, M. B. Latif, S. Lavoie, K. G. Leach, B. G. Lenardo, K. K. H. Leung, H. Lewis, G. Li, X. Li, Z. Li, C. Licciardi, R. Lindsay, R. MacLellan, S. Majidi, J. Masbou, M. Medina-Peregrina, S. Mngonyama, B. Mong, D. C. Moore, K. Ni, I. Nitu, A. Nolan, S. C. Nowicki, J. C. Nzobadila Ondze, J. L. Orrell, A. Pena-Perez, H. Peltz Smalley, A. Piepke, A. Pocar, E. Raguzin, R. Rai, H. Rasiwala, D. Ray, S. Rescia, F. Retiere, G. Richardson, V. Riot, N. Rocco, R. Ross, S. Sangiorgio, S. Sekula, T. Shetty, L. Si, V. Stekhanov, X. L. Sun, S. Thibado, T. Totev, S. Triambak, R. H. M. Tsang, O. A. Tyuka, E. van Bruggen, M. Vidal, S. Viel, Q. D. Wang, M. Watts, W. Wei, M. Wehrfritz, L. J. Wen, S. Wilde, M. Worcester, X. M. Wu, H. Xu, H. B. Yang, L. Yang, M. Yu, O. Zeldovich, J. Zhao

Abstract

Noble liquid time projection chambers (TPCs) are a leading technology in the detection of ionizing radiation, particularly in applications such as accelerator neutrino physics, dark matter detection, and neutrinoless double beta decay. This paper addresses the design considerations for implementing stable high voltage (HV) systems within large noble liquid TPCs, with a focus on the nEXO experiment. Utilizing insights from prior HV research and experimental investigations, we outline factors influencing HV stability and discuss design choices to improve stability and prevent electrical discharges. A novel HV delivery system concept is presented, tailored for the nEXO TPC, which incorporates these design considerations while also meeting the stringent radiopurity requirements of the nEXO neutrinoless double beta decay search. These design considerations and their specific implementation towards a HV delivery system offer guidance to future experiments applying high voltage in noble liquid environments.

Design of a high voltage delivery system for noble liquid time projection chambers

Abstract

Noble liquid time projection chambers (TPCs) are a leading technology in the detection of ionizing radiation, particularly in applications such as accelerator neutrino physics, dark matter detection, and neutrinoless double beta decay. This paper addresses the design considerations for implementing stable high voltage (HV) systems within large noble liquid TPCs, with a focus on the nEXO experiment. Utilizing insights from prior HV research and experimental investigations, we outline factors influencing HV stability and discuss design choices to improve stability and prevent electrical discharges. A novel HV delivery system concept is presented, tailored for the nEXO TPC, which incorporates these design considerations while also meeting the stringent radiopurity requirements of the nEXO neutrinoless double beta decay search. These design considerations and their specific implementation towards a HV delivery system offer guidance to future experiments applying high voltage in noble liquid environments.
Paper Structure (21 sections, 2 equations, 10 figures)

This paper contains 21 sections, 2 equations, 10 figures.

Table of Contents

  1. Introduction
  2. Design considerations for long term HV stability
  3. Maximum electric field strength
  4. Area and volume effects
  5. Materials
  6. Electrodes
  7. Insulators
  8. Insulator surface geometry
  9. Liquid thermodynamics and purity
  10. HV experience from EXO-200
  11. nEXO HV delivery
  12. nEXO overview
  13. nEXO HV system overview
  14. HV power supply and filters
  15. HV cable
  16. ...and 6 more sections

Figures (10)

  • Figure 1: One half of the EXO-200 double TPC. The etched phosphor bronze cathode grid at the top in the photo also serves as the cathode for the other half of the TPC which is symmetrically placed above. Note the PTFE panels on the interior wall of the field cage, and the Al/MgF2 coating of the copper LAAPD platter, both designed to improved reflectivity for VUV light.
  • Figure 2: A: Overview of nEXO HV delivery system. It consists of a HV power supply and filter (not shown) that connects to a pressure-rated HV-feedthrough (inset B, with more details in Fig. \ref{['fig:warm_seal']}) which contains a room-temperature xenon-air seal around a continuous HV cable. The cable runs through a conduit that passes through the water tank and HFE cryostat and connects at the bottom of the TPC vessel (inset C) with a HV connection which delivers voltage to the cathode.
  • Figure 3: Circuit diagram of the HV power supply, noise filter, and glitch detector system. $V_{out}$ connects to the TPC cathode through a HV cable and $G_{out}$ connects to the oscilloscope for the glitch detector. $R = 10MΩ$, $C = 1nF$, and $R_1 = 1MΩ$. See text for details.
  • Figure 4: High voltage cable from Dielectric Sciences, Inc. (cable DWG NO. 2353). From the center moving outwards, the cable consists of: Semi-conductive PE conductive core (Layer A); LDHMW PE insulator (Layer B); Semi-conductive PE ground sheath (Layer C); Braided shield (Layer D); Outer jacket (Layer E).
  • Figure 5: A: Conceptual model of the room temperature gas seal around the HV cable on a customized 2.75in (69.8mm) CF flange. B: A prototype built and tested in the lab showing the modified Swagelok® Ultra-Torr fitting, and the double O-ring.
  • ...and 5 more figures